<template>
  <view>
    <!-- 搜索框 -->
    <my-search @click = "gotoSearch"></my-search>
    <!-- cate分类页面 -->
    <view class="scroll-view-container">
      <!-- 左侧的滚动视图区域 -->
      <scroll-view class="left-scroll-view" scroll-y="true" :style="{height:wh + 'px'}">
        <block v-for = '(item,i) in cateList' :key='i'>
          <view :class="['left-scroll-view-item',i === active?'active':'']" @click="activeChanged(i)">{{item.cat_name}}</view>
        </block>
      </scroll-view>
      <!-- 右侧的滚动视图区域 -->
      <scroll-view class="right-scroll-view" scroll-y="true" :style="{height:wh + 'px'}" :scroll-top="scrollTop">
        <view class='cate-lv2' v-for="(item2,i2) in cateLevel2" :key="i2">
          <view class="cate-lv2-title">
            / {{item2.cat_name}} /
          </view>
          <!-- 三级分类 -->
          <view class="cate-lv3-list">
            <!-- item项 -->
            <view class="cate-lv3-item" v-for="(item3,i3) in item2.children" :key="i3" @click="gotoGoodsList(item3.cat_id)">
              <!-- 图片 -->
              <image :src="item3.cat_icon" alt = "item3.cat_icon"></image>
              <!-- 文本 -->
              <text>{{item3.cat_name}}</text>
            </view>
          </view>
        </view>
      </scroll-view>
    </view><!--  container -->
    
  </view>
</template>

<script>
  export default {
    data() {
      return {
        // 窗口的可用高度 = 屏幕高度 - navigationBar高度 - tabBar高度
        wh:0,
        cateList:[],
        active:0,
        cateLevel2:[],
        scrollTop:0
      };
    },//data
    onLoad(){
      //获取当前系统的信息
      const sysInfo = uni.getSystemInfoSync();
      //为wh窗口可用高度动态赋值
      this.wh = sysInfo.windowHeight-50;
      this.getCateList();
    },
    methods:{
      gotoSearch(){
        uni.navigateTo({
          url:'/subpkg/search/search'
        })
      },
      async getCateList(){
        const { data: res} =await uni.$http.get('/api/public/v1/categories');
        // console.log(res);
        if(res.meta.status!== 200){
         return uni.$showMsg();
        }
       this.cateList = res.message;
        // 渲染二级分类
        this.cateLevel2 = res.message[0].children
      },
      activeChanged(i){
        this.active = i;
        //二级列表重新赋值
        this.cateLevel2 = this.cateList[i].children;
        //scrollTop,跟原值一样的时候不让改，所以就从小小的0和1之间变化
        this.scrollTop = this.scrollTop === 0?1:0;
        
      },
      gotoGoodsList(cat_id){
        uni.navigateTo({
          url:'/subpkg/goods_list/goods_list?cid'+ cat_id
        })
      }//goto
    }//methods
  }//default
</script>

<style lang="scss">
.scroll-view-container{
  display: flex;
  .left-scroll-view{
    width:120px;
    .left-scroll-view-item{
      line-height: 60px;
      background-color: #f7f7f7;
      text-align: center;
      font-size: 12px;
      // 激活项的样式
      &.active{
        background-color: #ffffff;
        position: relative;
        //渲染激活项左侧的红色指示边线
        &::before{
          content: '';
          display: block;
          width: 3px;
          height: 30px;
          background-color: #c00000;
          position: absolute;
          left: 0;
          top: 50%;
          transform: translateY(-50%);
        }
      }
    }
  }
}

.cate-lv2-title{
  font-size: 12px;
  font-weight: bold;
  text-align: center;
  padding: 15px 0;
}
.cate-lv3-list{
  display: flex;
  flex-wrap: wrap;
  .cate-lv3-item{
    width: 33.33%;
    margin-bottom: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;
    image{
      width: 60px;
      height: 60px;
    }
    text{
      font-size: 12px;
    }
  }
}
</style>
